1. Field of the Invention
The present invention relates to the field of window shades.
2. Prior Art
Certain types of window shades have cords on the shade that are used to raise the shades, typically a manufacturer and/or installer, who would level the shade by tying evenly the cords to the bottom rings of the shade. This procedure provides satisfactory results, though can be both time consuming and frustrating, as tying the first cord at the desired height is relatively straightforward, but tying the second cord and successive cords at the exact position to obtain a level shade can be an elusive task. Further, adjusting the shade by an inexperienced homeowner and still obtaining a level shade can be even more difficult.
Also known in the prior art are plastic cord stoppers or cord locks frequently used on drawstrings to lock the drawstrings of cloth bags and the like, once the drawstrings are pulled to close or secure whatever item the drawstrings are on. These plastic cord stoppers or cord locks are generally characterized by a body having a button member fitting therein, with a coil spring between the body and the bottom of the button member. When the button member is depressed against the spring, a hole through the body member and a hole through the button member are generally aligned, allowing the passage of the cord therethrough. Release of the button member, however, allows the spring to force the button member upward to pinch the cord between the body and the button member.
Cord stoppers of this general configuration for stopping single cords or having two such sets of openings in the body and button member for stopping two cords in the same assembly are well known. The cords, of course, can be released by squeezing between the button member and the body to again align the holes, after which the cord freely passes through and can be adjusted with respect to the aligned holes in the stopper.
Such a stopper could theoretically be useful as a stopper for window shade cords. However, the commercially available stoppers are generally too large for this application, as the typical window shade cord is much finer than the line or rope for which such stoppers are designed to be used. Also, when such stoppers are scaled to a proper size for a window cord stopper, the stopper will not adequately grasp the window shade cord to avoid slipping on the cord during or after initial adjustment. Consequently, prior to the present invention, devices of this general character were not used for shade adjustment.